Can you travel from Spain to London by bus?

It is not possible to travel from Spain to London by bus without taking a ferry or a train through the Eurotunnel. There are no direct bus routes between Spain and London. You would need to take a bus to a port city in Spain, such as Santander or Bilbao, and then take a ferry to Portsmouth or Plymouth, UK. From there, you could take a train or a bus to London. Alternatively, you could take a bus to Paris, France and then take the Eurostar train to London.